Author Topic: 400/4 carb balancing  (Read 1652 times)

Offline THUNDERDOWNUNDER

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400/4 carb balancing
« on: May 21, 2020, 03:36:21 PM »
Think they need a balance . Sluggish takeoff then whoosh! Anyone know a good brand of vac gauges or ones  to avoid ? Thanks in advance!

Offline Bryanj

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Re: 400/4 carb balancing
« Reply #1 on: May 21, 2020, 04:30:52 PM »
If you want ones that work get Sealy, come with adaptors and pipe plus good gauges BUT over £100
The cheaper blue metal ones dont damp well, ive had both

Offline taysidedragon

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Re: 400/4 carb balancing
« Reply #2 on: May 21, 2020, 06:01:27 PM »
Or look for Morgan Carbtune, also cost a bit but reliable.
Gareth

1977 CB400F
1965 T100SS

Offline Bryanj

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Re: 400/4 carb balancing
« Reply #3 on: May 21, 2020, 07:34:37 PM »
Ebay 301337733424 are the ones i bought, there are £46ish sets on ebay from china BUT look at the dials closley they are utter crap.
These are the nearest to original Honda i have found and having done the job for as long as i have they are worth it, the others you may as well burn your cash

Offline Andych

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Re: 400/4 carb balancing
« Reply #4 on: May 22, 2020, 12:18:22 AM »
You could also go all high tech with this item from Australia... a bit more expensive but it is a quality product.
https://raytechautomotive.com/collections/frontpage/products/synchroking-4s-mkii
1975 CB400 - Project
1978 Yamaha SRX250 - Project

Offline gtmdriver

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Re: 400/4 carb balancing
« Reply #5 on: May 22, 2020, 08:10:54 AM »
I bought a cheapie set but I checked the calibration and, surprisingly, they were spot on.

Offline Bryanj

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Re: 400/4 carb balancing
« Reply #6 on: May 22, 2020, 08:39:55 AM »
I found the cheap set just didnt move tight when you screwed the little plastic damper down to stop the bounce, its those bits that are the real bad part the sealey one have the rotary thumbscrew dampers like the Honda.
I also paid less than £100 for mine on a "special" from e bay

Offline Bryanj

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Re: 400/4 carb balancing
« Reply #7 on: May 22, 2020, 06:07:51 PM »
Thats the cheap ones i was on about, sold mine for a tenner at an autojumble

Offline flatfour

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Re: 400/4 carb balancing
« Reply #8 on: May 23, 2020, 09:30:04 AM »
Perhaps it's just the luck of the draw - my Davida set of gauges are over 20 years old now, used a couple of times each year and have been faultless.

Offline 4wDaz

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Re: 400/4 carb balancing
« Reply #9 on: May 23, 2020, 09:49:56 AM »
Anyone used the Morgan Carbtune ?
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Offline taysidedragon

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Re: 400/4 carb balancing
« Reply #10 on: May 23, 2020, 10:17:40 AM »
Anyone used the Morgan Carbtune ?

Yep. Easy to use and good quality. My local club has a tool loan scheme so I just borrow it when I need it.
If I used it more I would buy one.
Gareth

1977 CB400F
1965 T100SS

Offline 4wDaz

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Re: 400/4 carb balancing
« Reply #11 on: May 23, 2020, 02:04:14 PM »
I think i may have to invest in a set  :)
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Offline Oggers

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Re: 400/4 carb balancing
« Reply #12 on: May 30, 2020, 05:22:00 PM »
You don't "need" any fancy stuff. I used 4 milk bottles - 1/3 full of water and red food colouring, 4 rubber bungs drilled to take the tubing, clear PVC fish tank tubing, and 4 x 5mm? adaptaors to take the hoses from each manifold. Cost about a tenner. The set up is a very cheap but effective manometer - details on You Tube plus many others. The goal is to ensure each carb pulls the same vacuum- doesn't matter what it actually is - and that the water level in the bottles ends up the same - or pretty close!. Fiddle with the carb screws and lock off until it is.

Arguably it is more accurate than cheap gauges as there is no calibration to worry about. My tickover is now pretty well sorted. Very little horrible primary chain rattle, good pick up, and very smooth throughout the revs. 

Offline liberamor

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Re: 400/4 carb balancing
« Reply #13 on: June 01, 2020, 04:17:59 PM »
hi everyone and sorry for my troubled english.
I have a yellow CB400F, i bought from a collegue in 2013. i have to say that this Honda  has neve goes well.
now i'm trying again to start the project (yes, my project is to have just a little ride).
ok.  I cleaned carburator, adjusted the contact but, when i try to balance the carbs, i have the fourth stuck instrument as in this video.
https://www.youtube.com/watch?v=r82bqi1UUFE&feature=youtu.be

The carbs component they are all original, i changed the oring only. which are the cause i can check to resolve this issue??

Thanks and really sorry for  my english
Gianni

Offline Bryanj

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Re: 400/4 carb balancing
« Reply #14 on: June 01, 2020, 04:55:59 PM »
You need to check the rubber manifolds to head and somewhere there is my write up on bench syncing carbs

 

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